WASHINGTON -- Sen. John McCain (R-Ariz.) on Tuesday defended former Massachusetts Gov. Mitt Romney as an advocate for immigration reform, despite glossing over the fact that the GOP presidential candidate doesn't support a pathway to citizenship for illegal immigrants, a key piece of comprehensive reform.

"He's already said that immigration reform is something that he's committed to," McCain told reporters, in response to a question about whether Romney should make the issue a bigger focus of his campaign.

(McCain discusses SB 1070 in interview with NBC affiliate KPNX above)

McCain, who unsuccessfully tried to advance comprehensive immigration reform legislation in 2007 with Sen. Ted Kennedy (D-Mass.), demurred when asked about Romney's opposition to creating a pathway to citizenship. That provision was a central piece of the McCain-Kennedy bill, along with a guest worker program and DREAM Act provisions.

"He said that he's committed to immigration reform," McCain said of Romney. "I think that's a pretty good statement."

The Arizona senator became agitated when asked about Romney having said he supports a self-deportation policy, whereby illegal immigrants would voluntarily go back to their country of origin and then apply for U.S. citizenship.

"No he hasn't. He's said that's one of the options he's looked at," McCain said. "So don't put words in his mouth."

Romney has explicitly said he supports such a policy, however. During a Republican debate in January, Romney was asked how he would address illegal immigration.

"The answer is self-deportation, which is people decide they can do better by going home because they can’t find work here because they don't have legal documentation to allow them to work here,” Romney said. “We’re not going to round them up.”

It's no secret that Romney -- and Republicans in general -- need to do more to win over Latino voters in November. In a closed-door speech to donors last week, Romney predicted that immigration would become a much larger issue in the campaign. He warned that recent polling shows Latinos overwhelmingly supporting President Barack Obama, something he said "spells doom for us."

McCain conceded Tuesday that Latinos have been put off by Republicans for several reasons.

"I think that immigration is certainly one of the issues, yeah," he said.

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